I got everything together to do Steven's bourbon brined maple smoked turkey except I can't find any maple wood chunks or chips Is there a substitute wood that I might use that would suffice in a bind? Thanks in advance for any suggestions.

I agree with Tbk420's advice - when the recommended wood isn't available IMO it's better to go with a lighter alternative instead of heavier. However, if you can't get enough fruitwood for the entire cook you can mix it with oak (I see you're in San Antonio) or hickory to lighten the smoke. Good luck, and please let us know how it turned out!